Pneumatic tires usually contain innerliner layers to retard permeation of air from the tire's cavity into the tire carcass. Such innerliner, or barrier, layers are usually in a form of layers comprised of butyl rubber or halogenated butyl rubber (sometimes referred to as halobutyl rubber) based rubber compositions which provide resistance to permeability of air.
To adequately promote resistance to air permeability, such innerliner is typically provided as a sufficiently thick layer which, in turn, may add significant weight to the tire.
Accordingly, various alternative thin air permeability resistant films have been proposed for pneumatic tire innerliners which are significantly lighter in weight. For example, and not intended to be limiting, see U.S. Pat. Nos. 4,928,741, 5,040,583, 5,938,869, 6,359,071, 6,376,598, 6,843,292, 6,861,470 and 8,544,517; U.S. Patent Publication Nos. 2001/0041762, 2013/0101821, 2013/0192736, 2013/0199686, 2014/0227499 and 2014/0242370; PCT Patent Publication Nos. WO/2006/1211140, WO/2007/050061, WO/2007/050236, WO/2007/070728, WO/2007/111584, WO/2008/051253, and European Patent Publication Nos. EP 0706878, EP 0722850, EP 1726620 and EP 1880871.
Various thin films of various polymers have been proposed for a tire innerliner layer comprised of, for example, a combination of thermoplastic resin which may contain a blend or dispersion of various polymers or copolymers.
The such films may be provided, for example, with a coating on one or both sides with an RFL (resorcinol/formaldehyde latex based) adhesive to promote adhering of overlapping ends of the sheet together, particularly where the sheet is placed on the circumferential inner surface of the tire.
For this invention, is desired to provide a pneumatic tire having an innerliner comprised of an innerliner film having an inner surface covering the tire carcass's surface in a circumferential direction and an outer surface adjacent to an internal air cavity of said tire, wherein the innerliner film has its two end portions overlapping each other to form a splice comprised of an inner first end portion adjacent to the tire rubber carcass and an outer second end portion adjacent to the internal air cavity of the pneumatic tire.
To enable and promote a durable splice for the innerliner film, it is proposed that the innerliner splice is comprised of:
(A) the overlapping inner first and outer second end portions of said innerliner film bonded through a first rubber strip positioned therebetween, wherein said first rubber strip extends in a circumferential direction beyond said splice on the inner surface of the innerliner film to further bond a combination of a surface of said inner end portion of the innerliner film, said inner surface of the innerliner film and said tire rubber carcass, and
(B) a second rubber strip abridging and bonded to the a surface of said outer second end portion of the innerliner film and outer surface of said innerliner film adjacent to the internal air cavity of said pneumatic tire.